Users of electronic books (“eBooks”) or similar devices are increasingly accessing content, such as text, video, graphics, etc. The content may include various types of visual aids or reference material that may enhance a user's understanding of the content. For example, these visual aids may summarize or organize information in content for the benefit of users. Presentation of the visual aids or references may be problematic, however, because they may not be dynamically updated as content changes. They may instead be static information that may unfortunately either become out-of-date as a user progresses through content, or may spoil future events in the content for users, neither of which are desirable.
Certain implementations will now be described more fully below with reference to the accompanying drawings, in which various implementations and/or aspects are shown. However, various aspects may be implemented in many different forms and should not be construed as limited to the implementations set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like numbers refer to like elements throughout.